Sunday, 22 February 2004

Gulf of Papua

Yesterday I told you I'd find out what happens to the sediment captured by the Jumbo Piston Core (JPC). Is the 40 feet of mud collected from the seabed going to the spa mud bath industry - or does something else happen?

Here's what I learned; while the team that does the coring finds their complexion does in fact improve after getting muddy while working with the JPC, it does not go for profit at spas. It turns out that after they cut out the pieces of PVC core liner and label it, the core then goes to an air-conditioned or refrigerated container set-up with a machine called a core logger. The core logger measures magnetic fields by sending segments of the core, on a conveyer belt through a series of sensors. The central section of the conveyer belt has four sensors that measure the core as it moves along the track. It moves like a turtle, one centimeter at a time, taking approximately - slowly - pushed through one centimeter at a time. The first sensor is a gamma ray source that basically "x-rays" the core to give the bulk density measurement. Next up are P-wave sensors that measure sound velocity and how much sound gets attenuated when it goes though the core. This is followed by measurement of the diameter of the core; this is used to calibrate the other measurements, and finally, the magnetic susceptibility loop. There are fourteen inches around this section on all sides where there is no metal. This sensor measures the metal within the core. Phew, that was a mouthful. Picture a car wash that sends your car (the core) through a series such as the water that sprays the underside of the car, the soap brushes, the water that rinses it and the air blower that dries it off. Then instead of a clean core, you end up with a scanned core. Check out the photo of the core logger in the slide show.

It's just about lunchtime; perhaps we can talk with Chef Ed and find out more about the galley on the Melville. Any guesses as to how much food is on board? Check back tomorrow to find out!

Today's weather and location at 0900 (nine hundred hours, military time for 9:00 am)
Air Temperature: 26°C (79°F)
Water Temperature: 29°C (84°F)
Salinity: 29.99 PSU
Barometric Pressure: 1010.8 mb
Relative Humidity: 84%
Depth: 31m (101 ft)

Longitude: 8°12.5934' S
Latitude: 144°26.109' E